#
# Simple PWM controller
# Remote control tool
#
# Copyright (c) 2018-2021 Michael Buesch <m@bues.ch>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#

__all__ = [
    "Blocker",
]

class Blocker(object):
    """'with'-statement based single threaded blocker.
    This is _not_ a multi-thread lock.
    """

    def __init__(self, initialCount=0):
        self.__count = initialCount
        assert self.__count >= 0

    def __enter__(self):
        """Enter the blocking context.
        """
        assert self.__count >= 0
        self.__count += 1

    def __exit__(self, exc_type, exc_value, traceback):
        """Exit the blocking context.
        """
        self.__count -= 1
        assert self.__count >= 0

    def __bool__(self):
        """Returns 'True', if the action is blocked.
        """
        return self.__count > 0

# vim: ts=4 sw=4 expandtab
